The present invention relates to an engine room-cooling control system, which is adapted to cool the engine room in an improved manner after stoppage of the engine.
Conventionally, as a system for cooling the engine room of an automotive vehicle, a ventilating system has been proposed by Japanese Utility Model Publication (Kokoku) No. 55-34101, which comprises an electric fan which is mounted on a bonnet etc. for auxiliary ventilating purposes and is driven depending on the engine room temperature or the engine coolant temperature. The ventilating system is applied to an automotive vehicle where a radiator fan is mechanically connected to the drive shaft of the engine to compensate for decrease in the amount of cooling air supplied by the radiator fan under certain operating conditions of the engine such as idling.
However, the conventional system cannot properly cool the engine room after stoppage of the engine. More specifically, when the engine is stopped, the radiator fan, which is mechanically associated therewith, is also stopped, and air cooling by the radiator fan cannot be carried out. Further, after stoppage of the engine, the aforesaid auxiliarly electric fan is started and stopped only manually by the driver of the vehicle. Therefore, the driver must stay in the vehicle.
Further, the start and stop of the electric fan depends on judgement by the driver as to whether or not the engine room is under a condition which necessitates air-cooling. Therefore, it is very difficult to carry out cooling of the engine room in response to the magnitude of load on the engine immediately before stoppage of the engine.
More specifically, the magnitude of load on the engine immediately before stoppage of the engine has a great influence on the temperature of the engine room and the rate of increase in the temperature immediately after stoppage of the engine. The temperature of the engine room and the rate of increase in the temperature are higher as the load on the engine immediately before stoppage of the engine is heavier. Therefore, in order to carry out accurate control of air-cooling of the engine room, the load on the engine, air stream which has been produced by running of the vehicle and has struck thereon, etc. must be taken into consideration. However, it is difficult for the driver to accurately decide the start and stop of the engine by taking the above-described factors into consideration, and hence the conventional system cannot properly carry out control of air-cooling of the engine room after stoppage of the engine.
Further, a cooling system in which a fan for cooling the engine can be reversely rotated has been proposed by Japanese Utility Model Publication (Kokoku) No. 50-37473. However, the reverse rotation of the fan in the cooling system is only for prevention of excessive cooling of the engine.